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1
Dunn, Meredith M. « Relocation of Eastern Tennessee Earthquakes Using hypoDD ». Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/10085.
Texte intégralRésumé :
The double difference earthquake location algorithm, implemented in the program HYPODD, was used to relocate a data set of approximately 1000 earthquakes in the eastern Tennessee seismic zone (ETSZ), using a recently developed velocity model. The double difference algorithm is used to calculate accurate relative hypocenter locations by removing the effects of un-modeled velocity structure. The study examines the earthquake hypocenter relocations in an effort to resolve fault orientations and thereby gain insights into the tectonics of the seismic zone. The analysis involves visual comparison of three-dimensional perspective plots of the hypocenter relocations oriented according to focal mechanism nodal planes derived from events within several, dense clusters of earthquakes.
The northwestern boundary of the seismic zone corresponds to the steep magnetic gradient of the New York-Alabama lineament. The double-difference relocations reinforced previous interpretations of a vertical boundary between seismic and relatively aseismic crust at that location. Areas at the northeastern and southwestern ends of the ETSZ exhibit northwest trending hypocenter alignments, which are perpendicular to the overall northeastern trend of the seismic zone. These alignments agree with focal mechanism nodal plane orientations and are interpreted as seismogenic faults. In the central, most seismically active portion of the ETSZ, relocations appear to indicate a diffuse zone of hypocenters that are west-striking and north-dipping. The orientation of this zone of earthquake hypocenters is consistent with an existing seismic reflection profile that images mid to upper crustal reflectors with apparent dips of approximately 35 degrees to the north.
The interpreted fault planes are all consistent with an east-northeast oriented, sub-horizontal maximum regional compressive stress, consistent with findings in previous studies.Master of Science
2
Ramachandran, Selvaraj. « Hypoid gear optimization ». PDXScholar, 1992. https://pdxscholar.library.pdx.edu/open_access_etds/4419.
Texte intégralRésumé :
A hypoid gear optimization procedure using the method of feasible directions has been developed. The objective is to reduce the gear set weight with bending strength, contact strength and facewidth-diametral pitch ratio as constraints. The objective function weight, is calculated from the geometric approximation of the volume of the gear and pinion. The design variables selected are number of gear teeth, diametral pitch, and facewidth. The input parameters for starting the initial design phase are power to be transmitted, speed, gear ratio, type of application, mounting condition, type of loading, and the material to be used. In the initial design phase, design parameters are selected or calculated using the standard available procedures. These selected values of design parameters are passed on to the optimization routine as starting points.
3
Cheng, Yuping. « Dynamics of Hypoid and Bevel Geared Rotor Systems ». The Ohio State University, 2000. http://rave.ohiolink.edu/etdc/view?acc_num=osu1391708583.
Texte intégral
4
Gill, Harnavpreet Singh. « Computationally Robust Algorithms for Hypoid Gear Cutting and Contact Line Determination using Ease-Off Methodology ». The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1587499768039312.
Texte intégral
5
Yang, Junyi. « Nonlinear Dynamics of Driveline Systems with Hypoid Gear Pair ». University of Cincinnati / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1336138173.
Texte intégral
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Karagiannis, Ioannis. « Tribo-dynamic analysis of hypoid gears in automotive differentials ». Thesis, Loughborough University, 2013. https://dspace.lboro.ac.uk/2134/12801.
Texte intégralRésumé :
Torsional vibrations in differentials of Rear Wheel Drive vehicles are of major importance for the automotive industry. Hypoid transmissions, forming the motion transfer mechanism from the driveshaft to the wheels, suffer from severe vibration issues. The latter are attributed to improper mesh between the mating gear flanks due to misalignments, variation of contact load and shifting of the effective mesh position. For certain operating conditions, the gear pair exhibits high amplitude motions accompanied with separation of the mating surfaces. Ultimately, single or even double-sided vibro-impact phenomena evolve, which have been related to noise generation. This thesis attempts to address these issues by effectively analysing the dynamic behaviour of a hypoid gear pair under torsional motion. The case study considered is focused on a commercial light truck. The major difference of the employed mathematical model to prior formulations is the usage of an alternative expression for the dynamic transmission error so that the variation of contact radii and transmission error can be accounted for. This approach combined to a correlation of the resistive torque in terms of the angular velocity of the differential enables the achievement of steady state, stable periodic solutions. The dynamic complexity of systems with gears necessitates the identification of the various response regimes. A solution continuation method (software AUTO) is employed to determine the stable/unstable branches over the operating range of the differential. The ensuing parametric studies convey the importance of the main system parameters on the dynamic behaviour of the transmission yielding crucial design guidelines. A tribo-dynamic investigation aims at expanding the dynamic model from pure dry conditions to a more integrated elastohydrodynamic (EHL) approach. Analytical and extrapolated solutions are applied for the derivation of the film thickness magnitude based on the kinematic and loading characteristics of the dynamic model. The temperature rise is governed mainly by conduction due to the thin lubricant films. The generated friction is also computed as a function of the viscous shear and asperity interactions. The effective lubricant viscosity is greatly affected by the pressure increase due to the resonant behaviour of the contact load. The final part of this work is involved with a feasibility study concerning the application of Nonlinear Energy Sinks (NES) as vibration absorbers, exploiting their ability for broadband frequency interaction. Response regimes associated with effective energy absorption are identified and encouraging results are obtained, showing the potential of the method.
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Park, Daehyun. « Development of Surface Wear and Lapping Simulation Models for Hypoid Gears ». The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1251739728.
Texte intégral
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Fossier, Charlotte. « Investigations on the efficiency of truck axles and their hypoid gear set : A thermo-mechanical model ». Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEI019.
Texte intégralRésumé :
Pour répondre au besoin des clients ainsi qu’aux réglementations gouvernementales, les constructeurs de camions doivent diminuer la consommation et les émissions de leurs véhicules. Une solution-clé est d’améliorer le rendement de la transmission du camion, dont le pont fait partie. Leur design n’a longtemps été optimisé qu’en fonction de critères de durabilité et de bruit. L’objectif de ce travail est donc de caractériser le rendement des ponts de camion. La dissipation de puissance au sein du pont est causée par l’engrènement, les roulements, les joints et le barbotage. Des méthodes permettent d’estimer globalement ces pertes de puissance, mais elles ne sont pas forcément adaptées aux ponts. En effet, l’élément principal du pont est un engrenage spiro-conique ou hypoïde et son importance est étudiée : sa forme influe sur le barbotage, tandis que sa géométrie de denture et sa cinématique gouvernent le frottement à l’engrènement. Il semble ainsi important d’évaluer le frottement de ces couples coniques par une approche locale et d’étudier l’influence des paramètres de denture. Cependant, les pertes de puissance dépendent de la température, via les propriétés de l’huile. Des expériences montrent un important écart de température entre les composants. Il faut donc considérer des températures locales plutôt qu’une température d’huile globale. Le rendement et la durabilité peuvent être impactés par des points chauds. La méthode des réseaux thermiques permet de modéliser les échanges thermiques du pont ainsi que la distribution de températures. Les tests classiques de rendement mesurent uniquement la perte globale et la température d’huile : rien ne permet de confirmer la répartition des pertes entre sources. Une campagne d’essais avec mesures de température est donc réalisée et valide le modèle pour le calcul des températures locales et pour l’estimation des pertes de chaque composant. Ce modèle peut alors être utilisé lors du design de futurs pontsTo fulfil customer demands, but also government regulations, the truck industry must decrease the fuel consumption and emissions of its vehicles. A key development is to improve the efficiency of the powertrain, which includes the axle. Until recently, optimisation of axle design has mainly concerned durability and noise aspects. The aim of this study is then to characterise the efficiency of truck axles. As for most of the mechanical transmissions, power dissipation in axles is due to gear mesh, rolling element bearings, seals and oil churning. Formulae already exist to estimate these power losses at a global level, but they are not always adapted to axles. Indeed, the main component of axles is a spiral bevel or a hypoid gear set. The influence of these special gears on efficiency is investigated here: their shape drives oil churning losses, while their tooth geometry and their kinematics impact friction at gear mesh. Therefore, the meshing friction of the gear set is also evaluated thanks to a local approach. The influence of some gear parameters is studied. However, power losses are influenced by temperature through oil viscosity. As previous experiments underline non-negligible temperature difference between components, it is necessary to consider local temperatures instead of a global oil temperature. Efficiency but also durability can be impacted by local hot spots. The thermal network method is used to model the thermal exchanges inside and outside the axle and to calculate temperature distribution. Usual efficiency tests on axles measure only global power loss and oil temperature: no evidence allows to confirm a power loss breakdown. Thus, a test campaign with temperature measurements is done and validates the model on local temperature calculation but also on estimation of component power losses. The model can be used at design stage for future development of axles
9
Klein, Alexander. « Spiral bevel and hypoid gear tooth cutting with coated carbide tools / ». Aachen : Shaker, 2007. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=015866212&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.
Texte intégral
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Fontana, Douglas. « Controle de vida da ferramenta do tipo lamina alternada Gleason no fresamento de coroas hipoidais ». [s.n.], 2003. http://repositorio.unicamp.br/jspui/handle/REPOSIP/265597.
Texte intégralRésumé :
Orientador: Anselmo Eduardo DinizDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica
Made available in DSpace on 2018-08-03T20:42:19Z (GMT). No. of bitstreams: 1 Fontana_Douglas_M.pdf: 10116872 bytes, checksum: 3a8e7469b54d02c31d22b732a5021bb1 (MD5) Previous issue date: 2003
Resumo: A transmissão de movimentos mecânicos através de engrenagens é muito utilizado em todos os segmentos industriais.O corte de dentes de engrenagens é uma operação bastante importante dentro da usinagem. Apesar de sua importância, este é um processo pouco estudado, pois esta é uma área bastante restrita de atuação. Emfunção disso,a maior parte dos desenvolvimentos relacionados à tecnologia de corte de dentes de engrenagens ocorre no meio industrial, geralmente de forma empírica. A determinação do fim de vida das lâminas de corte Gleasonsão feitas,no chão de fabrica,pelos preparadores ou mesmo pelos operadores das máquinas.Tal decisão é baseada em critérios altamente subjetivos e portanto, faz com que o tempo de utilização da ferramenta apresente uma grande variabilidade,ou seja, em determinados momentos, a ferramenta é utilizada além de sua vida efetiva e, em outros momentos, esta utilização se dá a quém da mesma. Caso a ferramenta ultrapasse sua utilização ótima, ocorrem vários problemas, dentre os quais: maior volume de material retirado na afiacão da ferramenta com conseqüente redução do númerode vidas desta, a rugosidademédia (Ra) das peças toma-se muito elevada,fazendo com que a japidação do dentado (operação posterior ao corte) seja muito demorada e portanto, anti-econômica.Por outro lado, se a ferramenta for sub-utilizada. ocorre um desperdício de lâmina,bem como um aumento do tempo de processamento pois um maior número de trocas da ferramenta vai ocorrer. Este trabalho procurou estabelecer um parâmetro objetivo de fim de vida da lamina de corte do tipo Hardac, utilizandoo processo de corte denominado Completo (Completing). Para tanto, foi feito um trabalho junto a um fubricante de auto-peças, que usina engrenagens cônicas e hipoidais, utilizada em diferenciais de caminhões e ônibus.O parâmetro escolhido foi a rugosidade média (Ra) do flancodos dentes das engrenagens. O comportamento e a dispersão da vida da ferramenta anterior e posterior à implantação do parâmetro proposto foram analisadas.Os resultados mostram uma maior uniformidade da vida das laminas de corte gleason,bem como dos tempos de afiação das mesmas e Iapidação do dentado. Além disso, as lâminas passaram a ser utilizadas de forma otimizadas em relação ao seu desgaste e à quantidades uperficial da peça. Um segundo objetivo do trabalho foi comparar a vida de ferramentas de aço rápido com algumas coberturas diferentes e também sem cobertura na superficie de saída, pois foram utilizadas após a afiação da ferramenta com cobertura total Pelo desempenho mostrado nos resultados a melhor cobertura foi aquela de nitreto de titânio originária do fabricante da ferramenta e do equipamento
Abstract: The transmission of mechanical motion through gears is very used in alI industrial segments.The cutting process of gears is a very important process in the manufacturing. Despiteits importance this is a process not so studied as it a very specific area. According to this, most part ofthe industrial field, usually in an empirical way. The determination to end the life of a Gleason Cutter Blade is made by machine operators. The decision is based on highly subjective criteria and as for this it makes the using time of this tool to presenta great variability. As resuh this tool is sometimes used longeror less than it should.If its use is longer exceedingits life time,many problems may occur, such as: bigger volume taken from the sharpening material of tools which results in a reduction of their lifetime, the average rougbness (Ra) of the parts becomes higher which makes lapping of the teeth (process which occurs after cutting) to take longer and as a resuh not economical.On the other hand,if the tool is used less there is a waste ofthe blade as well as an increasein the manutacturing process due to the change of tools. This work tried to establishan objetive parameteron the end ofthe life ofthe Hardac type ofblade, using a cutting process called Completing.For this reason this work was done together with an Automotive Company that produces beveland hypoidgears used on heavyduty drive axles for trucks and buses. The chosen parameter was the average rougtmess(Ra) ofthe teeth flankof the gears. The behavior and dispersion of the tool Jife before and after the setting of the proposed parameter were analized. The resuhs show a greater uniformity of the life the Gleason Cutter Blade as well as its sbarpeningtime and teeth lapping. Apart from it, the blades started to be used on an optimized way related to its wear and to the surlace quality of the piece. Another objetive of this work was to compare the high speed steel tool life with some different coats andalso no coating on theftont ceplane,as theywere used after the tool sharperning with total coat. For the result showed the best coating was the one with titanium nitrideoriginate dftom the tool and equipamentmanufacturer
Mestrado
Materiais e Processos de Fabricação
Mestre em Engenharia Mecânica
11
Gregefors, Carl. « Correlation study between FEA and physical testing for a hypoid gear set ». Thesis, KTH, Hållfasthetslära (Inst.), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-190100.
Texte intégralRésumé :
This thesis describes a correlation study of gear tooth bending stresses between physical testing and Finite Element modelling. It was conducted after a discovery at GKN that there were inconsistencies between the measured and calculated tooth root stresses for a hypoid gear set. The aim of the thesis was to investigate to what extent the stresses are correlated and if the program used is reliable for bending stress calculation. This would then be used to create S/N-curves for the gear set. The correlation was studied for several different aspects of the gear set. The contact pattern for the gear set was compared visually for a range of torque levels to see how well they matched and if this would contribute to the discrepancy. The root bending stress had been measured using a number of strain gauges in the root of the teeth. The location of these strain gauges was measured using a digital microscope and coordinate-measuring machine and the strain in the corresponding location in the Finite Element model was evaluated. The calculated contact pattern showed a slight under-approximation for lower torque levels but the agreement increased with increasing torque levels. The stress showed good correlation in the highly stressed middle area of the tooth for both the pinion and the ring gear while the lowly stressed heel and toe were worse. As the maximum stress is the deciding factor for bending fatigue the program was deemed reliable and the results used to evaluate fatigue life for the gear set.Detta examensarbete beskriver en korrelationsstudie för böjspänningen i kuggrötter där finita element-simuleringar jämförs med fysiska testresultat. Korrelationsstudien utfördes då GKN upptäckte att det var inkonsekvent överensstämmelse mellan uppmätta och beräknade böjspänningar i kuggroten i en hypoidkuggväxel. Syftet var således att säkerställa till vilken grad spänningarna var korrelerade och om det program som använts är pålitligt vad gäller böjspänningsberäkningar. Ett flertal aspekter undersöktes i korrelationsstudien. En okulär jämförelse mellan det den beräknade och den uppmätta kontaktarean gjordes för ett intervall av momentnivåer för att fastställa hur väl de stämde och för att se om det kunde bidra till diskrepansen i spänningsjämförelsen. Böjspänningen mättes i testet med ett antal trådtöjningsgivare monterade i kuggroten. Dessa givares position mättes upp med hjälp av ett digitalt mikroskop och en koordinatmätningsmaskin. Samma spänning mättes sedan upp i motsvarande område i den finita element-modellen. Den uppmätta kontaktarean var något underskattad för låga momentnivåer men vid högre nivåer var korrelationen god. I områden med hög böjspänning i kuggroten var korrelationen mellan test och simulering god. I kuggtändernas tå och häl var korrelationen sämre. Då det intressanta området är det med hög spänning ansågs programmet var tillräckligt exakt för att användas för att skapa utmattningsdiagram från testdata.
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Klein, Alexander [Verfasser]. « Spiral Bevel and Hypoid Gear Tooth Cutting with Coated Carbide Tools / Alexander Klein ». Aachen : Shaker, 2007. http://d-nb.info/1166510123/34.
Texte intégral
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Erkilic, Erdem. « A Model to Predict Pocketing Power Losses in Spiral Bevel and Hypoid Gears ». The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1337616576.
Texte intégral
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Vittal, Srigiripura Sahana. « Development of a method for estimation of contact fatigue life in hypoid gears ». Thesis, KTH, Maskinkonstruktion (Inst.), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-288898.
Texte intégralRésumé :
Hypoid gears have been used extensively in automobiles, aerospace, marine and other applications for decades. The special advantages of hypoid gears come with inherent contact complexities of varying curvature and sliding in both profile and lengthwise direction. Spalling failure is catastrophic and needs to be addressed with deeper roots in gear design. Analytical methods present several limitations. Iterative development from experimentation is expensive and time consuming with different nonlinear parameters difficult to interpret. This thesis aims to develop a method to calculate contact fatigue life for initiation of spalling using finite element methods. Experiments have played a major role in understanding the causal factors for failure, determining the fatigue life and to study the major system design parameters. A failure analysis of the fractured flank is performed. It clarified the design causal factors for failure and the mechanism of failure. Pinion being the vulnerable part is the focus of this thesis, a finite element model was developed on ANSOL HFM and the residual stresses were superposed on MSC Marc. A finite element fatigue analysis is performed on FEMFAT and the component fatigue life is determined. The calculated fatigue life is compared with physical testing results using Weibull statistical analysis in combination with probabilistic bearing life models to formulate emphatical correlation methods. The goal of this thesis is to establish a method to estimate fatigue life by taking up example of computing subsurface fatigue life of a hypoid pinion. The influence factors like the method of contact analysis, different types of residual stresses due to case hardening and shot peening, fatigue criteria, friction, material properties are studied in this thesis to develop a conscience for the methodology to computing contact fatigue life. The bulk material properties based on hardness represented fatigue properties more accurately. Scaled normal stress in critical plane fatigue criteria was found more suitable for contact analysis with pre-stresses and multi-axial non-proportional contact stress state on FEMFAT. Finite element based contact analysis method was found to be more suitable for subsurface fatigue life estimation despite the inherent advantages of the hybrid surface integral method and its accurate representation of friction. It was found that inclusion of friction in model did not change the fatigue life significantly, showing that the influence of hardness, surface topographies lubrication and contact temperature on shear stresses are too large to be neglected. Contact fatigue life increased by a factor of 4.4 times due to shot peening of gears in comparison with case hardening indicating the influence of residual stresses. For the estimation of fatigue life at the initiation of failure, a complete correlation with the fatigue test results could not be achieved and reasons for deviations were clearly identified. The area of damage indicated by this computation method correlated with the damage observed during tests. The observations and calculations indicated premature failure of pinion with explanation of mechanism of failure of pinion flank using contact conditions.Hypoidväxlar har använts i stor utsträckning i bilar, flyg-, marin- och andra applikationer under årtionden. De speciella fördelarna med hypoidväxlar kommer med inneboende kontaktkomplexitet med varierande krökning och glidning i både profil och längdriktning. Spallingfel är katastrofala och måste hanteras med grundlig redskapsdesign. Analytiska metoder har flera begränsningar. Iterativ utveckling baserad på experiment är dyrt och tidskrävande med olika icke-linjära parametrar som är svåra att tolka. Denna avhandling syftar till att utveckla en metod för att beräkna kontaktutmattningslivslängden för initiering av spalling med finitaelementmetoden. Experiment har spelat en viktig roll för att förstå orsaksfaktorerna för fel, bestämma utmattningslivslängden och för att studera de viktigaste systemdesignparametrarna. En felanalys av den skadade kuggflanken utfördes, vilket förtydligade felens orsaksfaktorer och den underliggande felmekanismerna. Driften är fokus för denna avhandling, en finitaelementmodell utvecklades med ANSOL-HFM och restspänningarna överlagrades med FEM-verktyget MSC-Marc. En slutlig elementutmattningsanalys utfördes med FEMFAT och komponentens utmattningstid bestämdes. Den beräknade utmattningslivslängden korrelerades med fysiska provningsresultat genom att tillämpa statistisk Weibullanalys i kombination med probabilistiska livslängdsmodeller. Målet med denna avhandling är att utveckla en metod för att uppskatta utmattningslivslängden och att tillämpa metoden för att beräkna bulkmaterialets utmattningslivslängd för ett hypoidrev. Påverkningsfaktorer som metoden för kontaktanalys, olika typer av restspänningar på grund av ythärdning och kulblästring, utmattningskriterier, friktion, materialegenskaper studeras i denna avhandling för att utveckla denna metod för att prediktera kontaktutmattningslivslängden. Bulkmaterialegenskaperna för hårdhet representerade utmattningsegenskaperna mera exakt. Skalad normalspänning i kritiska planutmattningskriterier befanns vara mer lämplig för kontaktanalys med förspänningar och multi-axiell icke-proportionell kontaktspänningsstatu än andra egenskaper med FEMFAT. Metodbaserad kontaktanalysmetod visade sig vara mer lämplig för uppskattning av ytutmattningslivslängd trots de inneboende fördelarna med hybridytaintegralmetoden och dess mera exakta friktionsrepresentation. Det visade sig att inkludering av friktion i modellen inte markant förändrade livslängden, vilket visade att påverkan av hårdhet, smörjning av ytorna och kontakttemperatur på skjuvspänningarna är för stor för att försummas. Kontaktutmattningslivslängden ökade med en faktor 4,4 gånger på grund av kugghjulning jämfört med ythärdning, vilket indikerar restspänningspåverkan. För att uppskatta utmattningslivslängden vid inledningen av ytfel kunde en fullständig korrelation med utmattningstestresultaten inte uppnås och orsakerna till avvikelser identifierades tydligt. Det skadade område som indikeras av denna beräkningsmetod korrelerade väl med den skada som observerades under testerna. Observationerna och beräkningarna indikerade tidigt fel i kuggen med förklaring av mekanismen för fel hos kuggflanken med hjälp av aktuellt kontaktförhållande.
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Peng, Tao. « Coupled Multi-body Dynamic and Vibration Analysis of Hypoid and Bevel Geared Rotor System ». University of Cincinnati / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1282931782.
Texte intégral
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Hua, Xia. « Hypoid and Spiral Bevel Gear Dynamics with Emphasis on Gear-Shaft-Bearing Structural Analysis ». University of Cincinnati / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1289944847.
Texte intégral
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Jeon, Soo Il. « Improving efficiency in drive lines : an experimental study on churning losses in hypoid axle ». Thesis, Imperial College London, 2010. http://hdl.handle.net/10044/1/5861.
Texte intégralRésumé :
The research concerns improvement of the power efficiency of lubricated components in automotive drivelines such as transmissions and axles. Meshed gear pairs, rolling bearings, seals and oil churning by rotating components immersed in the oil are studied. The purpose of the research is to explore the most effective way of improving the efficiency in drivelines, focusing on an axle comprising hypoid gears and a differential assembly. First, a study of the nature of losses affecting the efficiency of a simple spur gear box was carried out, and a model of friction and churning in a simple transmission was developed. Next, a detailed experimental study of oil churning losses in a hypoid axle from a four wheel drive road vehicle was carried out using the inertia run-down technique. To perform the above experiments, a new test rig for measuring oil churning losses was designed, manufactured and commissioned. The test rig allowed a wide range of speed and lubricant parameters to be explored and was designed by the author for tests available at different roll and pitch attitudes. In addition, an "extended" housing, consisting of a modified gear case that accepted the same internal components as the production axle but which had much greater internal clearances, was designed and manufactured. This enabled the effects of different casing geometry and of internal baffles to be studied. Additionally, the extension housing was modified to investigate the oil flow inside the housing through its one transparent side for the understanding of the effect of oil flow on churning losses. An investigation of design-related parameters influencing churning losses was carried out using the new test rig. Empirical equations for the churning losses, based on dimensional analysis, were developed to describe the test results. It was found that some combinations of baffles gave a significant reduction in losses. Supplementary tests were carried out using transparent windows to visualise the oil flow. These identified some of the mechanisms responsible for the reduction in churning loss and suggested a number of practical methods by which churning could be reduced without compromising the lubricant supply to remote components. It is argued that these innovations can contribute to improving fuel efficiency and limiting oil temperature rise in all-wheel-drive vehicles.
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Padmanabhan, Maadhav. « Utveckla en FE-modell för att studera effekten av presspassning på en hypoid växelsats ». Thesis, KTH, Maskinkonstruktion (Inst.), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-225872.
Texte intégralRésumé :
Gears are an integral part of devices ranging from simple wrist watches to complex systems like automotive and wave energy converters. They play a very important role in the transfer of torque. There are several types of gears to be chosen from, depending on the application. This thesis work deals exclusively with hypoid gears. A hypoid gear is a type of bevel gear, that transmits torque between two non-parallel shafts. It is similar to a spiral bevel gear, except that the pinion axis can be oset. It is this ability to offset, that renders hypoidgears as highly sought-after gears for automotive applications. It is crucial that these hypoid gears are designed efficiently and that their life before failure is predictable, to a reasonable degree of accuracy. To enable such predictions, this thesis makes an effort to build a finite element (FE) model. With the developed FE model, a study of the effect of press-fit on the ring gear's root bending stresses, that is present in a hypoid gear set of a car's Rear-Drive Unit (RDU), was carried out. The FE model was built on three different software - Transmission 3D (T3D), Hypoid Face Milled (HFM) and MSC Marc (Marc). The effect of press-fit on root bending stresses of the ring gear was first analyzed on T3D. To determine if the press-fit was correctly induced, the model was rebuilt and analyzed on Marc. HFM was used to determine the effect of inclusion of different components on the root bending stresses. Additionally,the HFM model was also replicated on Marc and a press-fit of 100m was induced. This was done to see if modelling the press-fit on HFM gave similar results to that of T3D and if using HFM in conjunction with Marclead to a better modelling procedure. It was found that the maximum root bending stresses increased linearly with increasing press-fit dimension. It was also found that the inclusion of different parts does not cause a significant increase in root bending stresses, except for the inclusion of differential cage. The effect of press-fit could not be quantified despite knowing that it affects the root bending stresses. When the same analysis done on HFM or T3D was done on Marc, there wasa 10% increase in stresses at highly stressed zone in Marc model of T3D; there was 10-15% increase in stresse sat highly stressed zone in the HFM model of Marc. Hence, quantification remained an impediment. It was not possible to quantify the error that occurred during the migration of analysis from HFM or T3D to Marc. However, potential causes of these errors could be the error in computation of bearing forces and difference in the definition of contacts in the software. Owing to large computational time and limited working period, all the analysis on Marc was carried out for one position and for the first time step of the gear mesh. If the errors in migration of analysis from one software to another could be quantified, then this modelling can be used to estimate the contribution of press-fit to rootbending stresses on the ring-gear. Although the contact pattern comparison between the virtual models andthe physical test suggests that HFM is a more trustworthy software, it is recommended to conduct some straingauge measurements on different ring gear teeth and then compare the results with those of the virtual model.Kugghjul är en integrerad del av utrustningar som sträcker sig fråan enkla armbandsur till komplexa system som bilar eller vågfrakftverkomvandlare. De spelar en mycket viktig roll vid överföring av vridmoment. Det finns flera typer av kugghjul som man kan välja från, beroende på applikationen. Detta projekt handlar exklusivt om hypoidväaxlar. En hypoidväxel är en typ av vinkelväxel som överför vridmoment mellan två icke parallella axlar. Det liknar ett spiralformat växel, förutom att kugghjulets axel kan förskjutas. Det är denna förmåga att kompensera, vilket gör hypoidväxlar en mycket eftertraktade redskap för fordonsapplikationer. Det är avgörande att dessa hypoid-redskap är konstrueras effektivt och att deras liv före misslyckande ar förutsägbart, i en rimlig grad av noggrannhet. För att möjliggöra sådana Förutsägelser gör denna avhandling ett försök att bygga en finita-element (FE) modell. Med den utvecklade FE-modellen utfördes en studie av effekten av presspassning pa ringvaxelns rotböjspänningar, som finns i en hypoid växelsats av en bilens Bakre enhet (RDU). FE-modellen byggdes på tre olika programvaror: Transmission 3D (T3D), Hypoid Face Milled (HFM) och MSCMarc (Marc). Effekten av presspassning på riggböjspänningarna hos ringväxeln analyserades först på T3D. För att bestämma om presspassningen var korrekt inducerad, byggdes modellen och analyserades på Marc. HFM användes för att bestämma effekten av inkludering av olika komponenter på rotböjspänningarna. Dessutom replikerades HFM-modellen också på Marc och en presspassning på 100 microns inducerades. Detta gjordes för att se om modellering av presspass på HFM gav liknande resultat som T3D och om man använde HFM i kombination med Marc leder det till ett bättre modelleringsförfarande. Det visade sig att de maximala rotböjspänningarna ökade linjärt med ökande presspassningsdimension. Det konstaterades ocksåa att införandet av olika delar inte orsakar en signifikant ökning av rotböjspänningar, utom införandet av differentialbur. Effekten av presspassning kunde inte kvantifieras trots att man vet det påverkar rotböjspänningarna. När samma analys gjord på HFM eller T3D gjordes på Marc, fanns det en 10% ökning av späanningar vid starkt stressad zon i Marc-modellen av T3D; det var 10-15% ökning av spänningar vid starkt stressad zon i HFM-modellen av Marc. Därför förblev kvantifiering ett hinder. Det var inte möjligt att kvantifiera felet som inträffade under analysanalysen från HFM eller T3D till Marc. Dock kan potentiella orsaker till dessa fel vara felet vid beräkning av bärkrafter och skillnad i definitionen av kontakter i programvaran. På grund av stor beräkningstid och begränsad arbetstid utfördes all analys på Marc för bara en position och för det forsta steget av växelns nät. Om felen i migration av analys från en programvara till en annan kunde kvantifieras, då kan denna modellering användas för att beräkna bidragen från presspassning till rotböjspänningar på ringväxeln. Även om kontaktmönstersjämforelsen mellan de virtuella modellerna och det fysiska testet föreslår att HFM är en mer pålitlig programvara, rekommenderas det att utföra en viss belastning Mätmätningar på olika ringväxeltänder och sedan jämföra sedan resultaten med dem från virtuella modellen.
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Wang, Jun. « Nonlinear Time-varying Gear Mesh and Dynamic Analysis of Hypoid and Bevel Geared Rotor Systems ». University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1186604249.
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Sugyarto, Eddy. « The Kinematic Study, Geometry Generation, and Load Distribution Analysis of Spiral Bevel and Hypoid Gears ». The Ohio State University, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=osu1392985391.
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Makam, Sandeep. « An Experimental Study on the Influence of Misalignments on the Static Transmission Error of Hypoid Gear Pairs ». The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1281992123.
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Xu, Hai. « Development of a generalized mechanical efficiency prediction methodology for gear pairs ». Columbus, Ohio : Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1128372109.
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Blettery, Hugo. « AN EXPERIMENTAL STUDY OF THE INFLUENCE OF MISALIGNMENTS ON THE LOADED TRANSMISSION ERROR AND ROOT STRESSES OF HYPOID GEAR PAIRS ». The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1480621750810372.
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Hotait, Mohammad Adel. « A Theoretical and Experimental Investigation on Bending Strength and Fatigue Life of Spiral Bevel and Hypoid Gears ». The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1296853688.
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Vaidyanathan, Sathyanarayanan. « Application of plate and shell models in the loaded tooth contact analysis of bevel and hypoid gears ». The Ohio State University, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=osu1335540802.
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Shi, Zhenghong. « Nonlinear Time-varying Dynamic Modeling of Vehicle Driveline Systems with Emphasis on Hypoid Gear Excitation and Response ». University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1490355055106922.
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Vogel, Olaf [Verfasser]. « Gear-Tooth-Flank and Gear-Tooth-Contact Analysis for Hypoid Gears : An Application of Singularity Theory / Olaf Vogel ». Aachen : Shaker, 2007. http://d-nb.info/1170528155/34.
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Kolivand, Mohsen. « DEVELOPMENT OF TOOTH CONTACT AND MECHANICAL EFFICIENCY MODELS FOR FACE-MILLED AND FACE-HOBBED HYPOID AND SPIRAL BEVEL GEARS ». The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1245266082.
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Nilsson, Fredrik. « Vascular endothelial growth factor (VEGF) inducerad angiogenes i skelettmuskulatur vid akut och kronisk hypoxi ». Thesis, Örebro universitet, Hälsoakademin, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-15942.
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Hang, Chao [Verfasser]. « Molecular genetics and electrophysiological studies of hypokalemic periodic paralysis (HypoPP) / Chao Hang ». Ulm : Universität Ulm. Medizinische Fakultät, 2002. http://d-nb.info/1015324568/34.
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Wang, Yawen. « Torque Load Effect on Multi-Point Mesh and Dynamics of Right-angle Geared Drives ». University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1384870250.
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Wang, Yawen. « Vibration and Sound Radiation Analysis of Vehicle Powertrain Systems with Right-Angle Geared Drive ». University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1491318542819425.
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Koronias, George. « Elastomultibody dynamics of RWD axle whine phenomena ». Thesis, Loughborough University, 2012. https://dspace.lboro.ac.uk/2134/9721.
Texte intégralRésumé :
Automotive industry is faced with numerous power train Noise, Vibration and Harshness issues. Particularly, in the driveline area of vehicles a noise commonly referred as differential axle whine which is a tonal response and becomes apparent under cruising conditions. This is one of the key concerns in rear wheel drive commercial vehicles. Although not a failure state, it is regarded as a quality issue and a source of annoyance, which can lead to warranty concerns. The associated cost of palliation to Ford Motor Company was estimated to be $25,000,000 in 2003. There have been several ways of studying axle whine through experimentation and numerical analysis. In this thesis, a new approach for investigating axle whine is highlighted, which is more integrative and detailed. Multi-body dynamics model of a light truck s driveline is developed with all the appropriate components, using constrained Lagrangian dynamics. Component flexibility is included for driveshaft pieces, rear axle half-shafts and the suspension elements. The connectivity of the components is accurately modelled such as the floating effect of rear half-shafts, linear bushings between driveline components to chassis connections, as well as the non-linear effect of tapered roller bearings, supporting the wheel hubs and gears. Furthermore, integrated to the previously described large scale model a detailed hypoid gear pair model is devised. This incorporates micro-scale physics for tooth contact analysis to predict geometric properties and deflections for the gear pair. At the same time thermo-elastohydrodynamic lubrication theory with non-Newtonian friction is applied. All these phenomena at different physical scales, such as large displacement rigid body dynamics and analytical equations for the detailed model are solved simultaneously, all within the same modelling environment. This multi-physics, multi-scale approach has not hitherto been reported in the literature, and constitutes a significant contribution to knowledge. Comparative studies of the model predictions and detailed vehicle tests are carried out, the combination of which points to resonant conditions in system responses and flexible component behaviour, coincident with the adverse conditions in the hypoid gear meshing. It is shown that vehicle drive and coast conditions, promoting teeth pair separations lead to irregular (improper) meshing of the differential gears. Such conditions induce impulsive actions that promote the axle whine phenomenon. This is a major finding of the research and contributes to a better understanding of the axle whine problem.
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Gränse, Agnes. « Jämförelse mellan markörer för funktionellt järnstatus på Siemens Advia 2120 och Sysmex XN-1000 ». Thesis, Linnéuniversitetet, Institutionen för kemi och biomedicin (KOB), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-36051.
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Syre transporteras från lungorna, via blodet bundet till erytrocyternas hemoglobin, till kroppens alla celler. En hemoglobinkoncentration i blodet under referensintervallet definieras som anemi och påverkar hela kroppen och försämrar den fysiska prestationsförmågan. Järnbristanemi är en anemi med otillräcklig järntillförsel till benmärgen på grund av tomma järnförråd (absolut järnbrist) eller försvårat järnutnyttjande (funktionell järnbrist). Analysparametern HYPO på analysinstrumentet Advia 2120 (Siemens) mäter andelen hypokroma erytrocyter (erytrocyter med lågt hemoglobininnehåll) och anses vara en av de bästa parametrarna för att påvisa funktionell järnbrist. Analysparametern Hypo-He på analysinstrumentet XN-1000 (Sysmex) är en forskningsparameter för samma ändamål. Syftet med detta arbete var att jämföra markörer för funktionellt järnstatus och utvärdera om analysen HYPO på Advia 2120 kan ersättas med Hypo-He på XN-1000. Fyrtiofyra patientprover, på vilka HYPO var beställt, analyserades, först på XN-1000 och därefter på Advia 2120. En linjär regressionmodell gjordes för att beskriva korrelationen mellan analyserna HYPO och Hypo-He. Imprecisionen för analysen Hypo-He beräknades genom inom-serie- och total-serie-imprecision. Korrelationen mellan analyserna var måttligt stark (r = 0,7185 (absoluta värden) och r = 0,8081 (logaritmerade värden)), dock med många analysresultat inom det lägre området. Variationskoefficienten för Hypo-He beräknades till mellan 0 % - 9,5 %. För att kunna avgöra om Hypo-He kan ersätta HYPO som indikator på funktionell järnbrist krävs kompletterande studier på välkaraktäriserade patientprover med varierande analysvärden inkluderande värden för HYPO på mer än 10 %.
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Eigner, Florian. « Untersuchungen am koaxialen Getriebe „HypoGear“ ». Technische Universität Chemnitz, 2019. https://monarch.qucosa.de/id/qucosa%3A34306.
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Auf der Suche nach immer kompakteren koaxialen Getrieben für kleine Antriebe steht eine neue Bauweise bereit. Der Foliensatz stellt kurz die Baugruppen eines solchen Getriebes vor und klärt über einige der Herausforderungen auf, die die Entwicklung beeinflussen. Weiterhin wird auf die Berechnung der verbauten Hypoidzahnradstufe eingegangen. Die Berechnung der Zahngeometrie ausgehend von den Wälz-Gleit-Körpern wird losgelöst von den Einschränkungen betrachtet, die herkömmliche Serienfertigungsverfahren mit sich bringen. Ausblickend werden die Entwicklungsschritte umrissen, die zunächst zum Prototyp und darüber hinaus zur Serienreife führen.
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Lotfy, Mamdouh M., et Ali S. Abdelsamad. « Survival function of hypo-exponential distributions ». Thesis, Monterey, California. Naval Postgraduate School, 1985. http://hdl.handle.net/10945/37406.
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The reliability of a system is the probability that the system will survive or complete an intended mission of certain duration. Describing all possible ways that a system can survive a mission in reliability shorthand gives a simple approach to reliability computations. Reliability computation for a system defined by shorthand notation is greatly dependent upon the convolution problem. Assuming constant component failure rates, this paper presents an analytical approach and a computer program for computing the reliability of any convolution of independent and exponentially distributed random variables.
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Caird, Lucy Elizabeth. « Hypo-oestrogenic states and bone density ». Thesis, University of Aberdeen, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335499.
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Osteoporosis is emerging as an important public health problem at an enormous cost to the National Health Service. This thesis observes the effects of certain states of hypo-oestrogenism, seen naturally during breast feeding and after the menopause, and the pathological states seen in hyperprolactinaemia and hypogonadotrophic amenorrhoea. It also observes the drug-induced situation resulting from the use of the gonadotrophin-releasing hormone analogue, goserelin. Bone density was measured using dual-energy X-ray absorptiometry (DEXA). This is very acceptable to subjects since the radiation dose is small and the low reproducibility makes short term longitudinal study possible. A biochemical assessment was also made measuring plasma osteocalcin and the cross-links pyridinoline and deoxypyridinoline excreted in the urine. In the group of early menopausal women we were unable to predict absolute BMD at either lumbar spine or femoral neck from personal risk factors. Body weight was the strongest predictor of bone density at each site. Rates of bone loss were greatest in the smokers and in those closest to their last menstrual period. The biochemical assessment was unhelpful. Those women with hypogonadotrophic hypogonadism had significantly lower bone density than age-matched normals. These were mainly young women with weight loss-related amenorrhoea. Those women with hyperprolactinaemia had a very normal bone density. In both groups no change in bone density was seen over the study period. The greatest reductions in bone density were seen in the breast feeding women and in those receiving treatment with the GnRH analogue, goserelin. In summary, the observed situations have resulted in changes in bone density. The magnitude of these changes are small and it is not clear how these small changes influence clinical outcome.
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Pelaccia, Thierry. « Comment les m??decins urgentologues raisonnent-ils au regard des sp??cificit??s de leur cadre et leur mode d???exercice ? » Thèse, Universit? ? de Sherbrooke, 2014. http://savoirs.usherbrooke.ca/handle/11143/126.
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Contexte : malgr?? les particularit??s de l???environnement de pratique de la m??decine d???urgence, il n???existe pas de recherches sp??cifiquement men??es sur la th??matique du raisonnement clinique dans cette sp??cialit??. Nous avons souhait?? mieux comprendre comment les m??decins urgentologues raisonnent dans le cadre de la prise en charge initiale des patients.
M??thode : une posture ??pist??mologique interpr??tative a ??t?? adopt??e ?? travers un devis de recherche qualitatif de type ethnographique. Des entretiens ont ??t?? r??alis??s aupr??s de m??decins urgentologues experts, ?? l???issue de la prise en charge d???un patient r??el. Ces entretiens reposaient notamment sur la visualisation de l???enregistrement vid??o en perspective subjective situ??e, obtenu gr??ce ?? l'usage d'une microcam??ra fix??e sur la tempe ou la branche de lunettes des praticiens.
R??sultats : les hypoth??ses diagnostiques sont g??n??r??es tr??s pr??cocement par les m??decins, parfois m??me avant la rencontre avec le patient, sur la base de la prise en compte d???un nombre tr??s limit?? d???informations, pour certaines contextuelles. Cinq hypoth??ses ??taient en moyenne g??n??r??es lors de la rencontre initiale et au moins une ??tait une hypoth??se de gravit??. Aucune n?????tait formellement ??limin??e ou valid??e sans r??sultats d???examens compl??mentaires. Un jugement pr??coce quant ?? la gravit?? de la situation permettait ??galement aux m??decins d???orienter leurs intentions initiales vers des buts diagnostiques ou th??rapeutiques. Les experts raisonnaient le plus souvent de mani??re intuitive. Ils prenaient en compte les sp??cificit??s de leur environnement professionnel en ??tant, par exemple, vigilants au temps, au caract??re potentiellement ??volutif de l?????tat clinique du malade et au devenir d???aval de celui-ci.
Conclusion : l???identification du raisonnement clinique des m??decins urgentologues offre des perspectives importantes en mati??re de pratique de la m??decine d???urgence, et de formation des r??sidents dans cette discipline. La m??thode originale de recueil des donn??es pourrait en outre ??tre r??exploit??e dans le cadre de travaux ult??rieurs.
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C, Gopalakrishnan Srikumar. « Tribodynamics of Right Angled Geared System ». University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1540566189193567.
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Engdahl, Philip, et Jesper Aspelin. « Kvalitetssäkring av fläckanalys för hypoidväxlar ». Thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-85961.
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Det amerikanska företaget Meritor är en globalt ledande leverantör av lösningar för bland annat drivlinor, bromsning och rörlighet till både industri- och kommersiella fordon. Meritor HVS AB:s fabrik, belägen i Lindesberg, är främst inriktad på montering av kompletta hjulaxlar samt bearbetning av komponenter, inklusive kugghjul till hypoidväxlar, till tunga fordon såsom buss och lastbil. Hypoidväxlar används i bakaxlar då de klarar av höga vridmoment samtidigt som de har en hög hållbarhet och är relativt tysta i drift. Ett steg i monteringsprocessen för växlarna på Meritor är att passa in pinjong och kronhjul, två typer av kugghjul, så att de har god kontakt mellan kuggarna. En god kontaktyta behövs för att inte påverka kugghjulens livslängd samt säkerställa tyst drift. Kontaktytan verifieras bland annat genom okulär fläckanalys av montören. Syftet med examensarbetet var att utföra en undersökning om hur kvalitetssäkringen av fläckanalysen kan förbättras i Meritors centrumväxelmontering. Visionsystem är en metod som ansetts lämpad och extra intressant att undersöka. Under arbetet har nuläget kartlagts genom bland annat observationer, intervjuer och interna dokument såsom arbetsinstruktioner. Undersökning av kvalitetssäkringslösningar har utförts genom bland annat studiebesök. Fem stycken lösningsförslag har tagits fram varav en kombination av några av dem skulle ge en mer fullständig kvalitetssäkring. För att bestämma exakt vilken lösning som är mest lämpad så behövs en kravspecifikation tas fram vilket i sin tur kan kräva att flera olika tester behövs genomföras för att kartlägga behov och önskemål.he American company Meritor is a globally leading provider of solutions for drivetrain, braking and mobility for both industrial and commercial vehicles. Meritor HVS AB's factory, located in Lindesberg, is primarily focused on the assembly of complete wheel axles and gears but also machining of components, including gears for hypoid gears, for heavy vehicles such as busses and trucks. Hypoid gears are used in rear axles as they can handle high torque while having a high durability as well as begin relatively quiet in operation. One step in the assembly process of the gears at Meritor is to fit the pinion and ring gears, two types of gears, so that they have good contact (mesh) between the gears. A good contact surface is necessary to not impact the life-span of the gears and to ensure quiet operation. The contact is verified through ocular contact spot analysis by the assembly worker, where the assessment may be a difficult task as well may differentiate between the assembly workers, which is a risk of false assessment. The aim of this project was to carry out a study regarding how quality assurance of the contact spot analysis can be done in Meritor's gear assembly. Vision systems are a method that is considered suitable and of extra interest to investigate. During the work, the current situation has been mapped through observations, interviews and internal documents such as operation instructions. Investigation of quality assurance solutions has been done through e.g. study visit. Five proposals for solutions have been developed where a combination of some of them would provide a more complete quality assurance. In order to determine exactly which solution that is most suited, a specification of requirements is needed to be determined. Several tests could be required to establish requirements and requests.
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Perera, Nevin Martin. « Phospholipase C activation is implicated in the responses of yeast to several stresses ». Thesis, University of Birmingham, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289301.
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Soueycatt, Mohamed. « Analyse épi/hypo-graphique des problèmes de points-selles ». Montpellier 2, 1991. http://www.theses.fr/1991MON20198.
Texte intégralRésumé :
L'analyse epigraphique des fonctions privilegie le role joue par l'epigraphe (par contraste avec l'approche classique ou c'est le graphe qui joue le role important) et s'applique tout naturellement a l'etude de problemes de minimisation en optimisation, calcul des variations. . . Cette demarche, naturelle lorsque l'on aborde les notions de convexite, semicontinuite s'est averee tres feconde egalement lorsque l'on s'interesse aux proprietes de differentiabilite, integration en analyse non reguliere. Ce point de vue a conduit a l'introduction de nouveaux concepts, epi-convergence, somme epigraphique, epiderivee, epi-integrales,. . . Jouant un role cle dans ces questions. La version hypographique, tout a fait symetrique, traite les problemes de maximisation. En vue de l'etude des problemes de points selles (plus particulierement convexes-concaves) nous developpons une analyse dite analyse epi/hypo graphique combinant les deux aspects precedents, epigraphique et hypographique. La somme et la multiplication epi/hypo graphique que nous avons introduites possedent des proprietes remarquables vis-a-vis des problemes de points-selles. A l'aide des metriques variationnelles de type hausdorff locales ou basees sur l'approximation moreau-yosida entre fonctions convexes-concaves, nous developpons une analyse quantitative concernant la stabilite des points selles
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Bächle, Alexander. « Die Verschmelzung zur Bayerischen Hypovereinsbank : eine rechtstatsächliche Untersuchung ; Vorstandspflichten, Wirtschaftsprüferhaftung, Rechtsschutz der Aktionäre - nach früherem und heutigem Recht / ». Marburg : Tectum-Verl, 2006. http://deposit.ddb.de/cgi-bin/dokserv?id=2779303&prov=M&dok_var=1&dok_ext=htm.
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Bächle, Alexander. « Die Verschmelzung zur Bayerischen Hypovereinsbank eine rechtstatsächliche Untersuchung ; Vorstandspflichten, Wirtschaftsprüferhaftung, Rechtsschutz der Aktionäre - nach früherem und heutigem Recht ». Marburg Tectum-Verl, 2005. http://deposit.ddb.de/cgi-bin/dokserv?id=2779303&prov=M&dok_var=1&dok_ext=htm.
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Gibbons, J. « Age-dependent susceptibility and immune hypo-responsiveness to Schistosoma mansoni ». Thesis, University of Cambridge, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.599372.
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It has been observed that adults and children have differences in their susceptibility to schistosome infection and reinfection. The relative importance of the various factors that may influence age-dependent innate resistance and acquired immunity to schistosome infection is uncertain. In order to assess this, juvenile and adult female Fischer rats were exposed to primary and secondary infections of Schistosomia mansoni. In contrast to the adult rats, juveniles were found to be harbouring significantly more worms at day 21 post-infection. After reinfection, both groups were equally resistant to challenge. Similar age-dependent susceptibility to infection was observed in rat mouse infections with Nippostrongylus brasiliensis. The effect of host hormones was assessed on larval schistosomes. Testosterone (but not DHEAS) was found to be schistosomicidal in vitro. Antibody responses (antigen-specific IgG, IgG1, IgG2a, IgG2b and IgG2c) were found to be lower in juvenile animals after primary infection. No significant differences were observed in the relative levels of anti-carbohydrate antibodies to parasite antigens. Intra-cellular cytokine staining revealed juveniles to have a more Th1 dominated cytokine profile than adults. Immunisation of juvenile and adult rats with ovalbumin resulted in lower levels of antigen-specific antibody in the juvenile group, even after subsequent boosting whilst sexually mature. To provide an experimental bridge between rodents and humans, juvenile and adult female. Rhesus monkeys were infected with S. mansoni. Juvenile monkeys had higher worm burdens (non-significant) with greater tissue and faecal egg counts compared to adults. However, circulating schistosome antigens (CAA) were significantly greater in infected juvenile monkeys. PBMC production of IL-4 and IL-5 was lower in juvenile animals following primary schistosome infection, as were parasite-specific antibody responses (IgG, IgG2, IgM and IgA).
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RIVIERE, DANIELLE. « Hypo-hdl-emies et lesions coronariennes chez le sujet normolipemique ». Aix-Marseille 2, 1988. http://www.theses.fr/1988AIX20483.
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Libreros, Bertini Ana Bolena. « Hypo- und viskohypoplastische Modellierung von Kriech- und Rutschbewegungen, besonders infolge Starkbeben / ». Karlsruhe : Inst. für Bodenmechanik und Felsmechanik, 2006. http://www.gbv.de/dms/goettingen/522379486.pdf.
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Connaghan, Kathryn P. « Jaw stiffness during speech by children with suspected hypo- or hypertonia / ». Thesis, Connect to this title online ; UW restricted, 2004. http://hdl.handle.net/1773/8206.
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Köthe, Dirk. « Veränderungen der Repolarisation bei hypo- und akinetischen Bewegungsstörungen der Hinterwand nach Coronardilatation ». Diss., lmu, 2005. http://nbn-resolving.de/urn:nbn:de:bvb:19-39013.
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LAUDOYER, YVES-MATTHIEU. « Chimiotherapie premiere et conservation laryngee dans les cancers hypo-pharynges et larynges ». Nice, 1992. http://www.theses.fr/1992NICE6553.
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